Write sum_multiples(n) that adds up every positive integer below n that is a multiple of 3 or of 5 (or both) and returns the sum.
Examples
Input: n = 10
Output: 23
Explanation: 3 + 5 + 6 + 9 = 23
Input: n = 3
Output: 0
Constraints
0 <= n <= 10**5
Goals
- Combine a loop with an or-condition
- Sum only the numbers that pass a test